Method and apparatus for the storage, refrigeration, and transportation of volatile liquids



Sept. 21, 1954 T c, w BRANDON 2,689,462

METHOD AND APPARATUS FOR THE STORAGE, REFRIGERATION, AND

TRANSPORTATION OF VOLATILE LIQUIDS 1 5 Sheets-Sheet 1 Original Filed July 16, 1948 Fig.

Clarence W. Branden INVENTOR.

Sept. 21, 1954 c, w, BRANDON 2,689,462

METHOD AND APPARATUS FOR THE STORAGE, REFRIGERATION, AND TRANSPORTATION 0F VOLATILE LIQUIDS Original Filed July 16, 1948 '5 Sheets-Sheet 2 2192 I98 1 a 206 I92 use 4 I94 I m i 9e as /0 v 1 I I88 7 m l I I 12: l a 76 2 l4 I /s/ I72 IN VEN TOR.

Clarence W Brandon Sept. 21, 1954 c. w. BRANDON 2,639,462 mamas AND APPARATUS FOR THE STORAGE, REFRIGERATION. AND

TRANSPORTATION OF VOLATILE LIQUIDS Original Filed July 16, 1948 5 Sheets- Sheet I5 a I u I I I I x 4 t I 5 x I I z I I i l I i I I i Q I I I I 1* s 2 I I I i I AI'Z- II z I I I I. 1 l (F-i I II I I N :2 I I l I I I I5 I I I i I I I I! I I Ii I N I I I I I; A I I IE 3 i v i" -I r Y j II N I 7 230 2 2/8 WWI/fir #416.

all 2 Q u v Clarence W Brandon 2 My/[ 5 INVENTORA 224 I /a2 1 Sept 21, 1954 c, w BRANDQN 2,689,452

llETl-{OD AND APPARATUS FOR THE STORAGE, REFRIGERATION. AND TRANSPORTATION 0F VQLATILE LIQUIDS Original Filed July 16, 1948 5 Sheets-Sheet 4 l Hg, 3 L 1 I Fig.8

iLL/l/ /I/I/l/l/l/ h g I ZL/l/l/l ////l Clarence W. Brendan IN V EV TOR.

WWW Mm,

Sept. 21, 1954 c. w. BRANDON 2,639,462

METHOD AND APPARATUS FOR THE STORAGE, REFRIGERATION. AND

TRANSPORTATION OF VOLATILE LIQUIDS Original Filed July 16, 1948 5 Sheets-Sheet 5 Clarence W Brandon INVENTOR.

WW Fm Patented Sept. 21, 1954 METHOD AND APPARATUS FOR THE STOR- AGE, REFRIGERATION, AND TRANSPOR- TATION F VOLATILE LIQUIDS Clarence W. Brandon, Tallahassee, Fla., assignor, by direct and mesne assignments, of forty-two and one-half per cent to N. A. Hardin, Hazel H. Wright, and Catherine H. Newton, Forsyth, Ga., and fifteen per cent to Harvey B. Jacobson, Washington, D. C.

Original application July 16, 1948, Serial No. 39,154.- Divided and this application July 27,

1951, Serial No. 238,964

21 Claims.

This invention relates to novel and useful improvements in a method and apparatus for the storage, refrigeration and transportation of volatile liquids and other fluids, and more particuvalues of about 450 pounds per square inch, at which pressures rupture of the container is threatened unless pressure relief is provided, these pressures arising directly and solely from the larly has reference to a method and apparatus for 5 thermodynamic expansive forces created in the improvin the transportation and storage of such liquid contents of the tanks by the heat of the fluids in barges, with particular attention to resuns rays or the like. Obviously, it has been necducing excessive temperatures and pressures genessary, therefore, to employ tanks of very thick erated in fluids which are confined in containers metallic plate construction, the example above and are exposed to external sources of heat. Almentioned usually requiring metal plates of 1%; though not limited to this field, my invention finds inch in thickness. a special utility in its application to a method It will be apparent that if some means were and apparatus for eflicaciously confining highly provided for reducing the pressures generated by volatile liquids, such as liquefied petroleum gases, the expansion of the liquid contents occasioned by ammonia, or the like, in tanks and in such a manthe above-mentioned source, and maintaining the ner that these tanks may constitute the essential portions of the hulls of barges and the like.

The present application is a division of my copending application, Serial No. 39,154, filed July 16, 1948, for Method and Apparatus for the Storage, Refrigeration and Transportation of Volatile Liquids and Other Fluids.

In its simpler aspects and broadest principles, the present invention represents an improvement upon and relates to somewhat similar subject matter to that disclosed in the prior patent of Clarence W. Brandon and George M. Brandon, Patent No. 2,408,505, patented October 1, 1946.

In the field of transportation and storage of volatile liquids, and especially in the use of tanks or barges which are designed to transport liquid upon waterways, it has been heretofore recognized as essential that the compartment receiving the volatile liquid shall be completely filled in order to avoid the detrimental effects of splashing or shiftin centers of gravity of a container which is partially filled and subjected to a rolling or tossing action during transit. Industry has long known that when such tanks are employed as barges or other portable containers and are completely filled with highly volatile or other liquids and subjected to external sources of heat, such as to the variable temperatures producedby the rays and heat of the sun, or the like, the increase in temperature of the liquids which completely fill and are confined in a storage compartment produces very great increases in the pressures to which such liquids are subjected.

By way of illustration, it may be noted that in one type of barge or tank, which is approximately 90 feet in length and about 9 feet in diameter, the pressures of the contained liquid where no vapor space is provided, and consequently to which the walls of the container are exposed, may rise from slightly aboveatmospheric pressureto maximum pressures thus generated to predetermined lower and safer limits that would normally occur with no provision for the relief of pressure, the tanks could be of much lighter material with a resultant appreciable economy in the constructing, handling and transporting of the same.

As a primary purpose, the invention aims to provide a tank for receiving volatile liquids which may be of appreciably lighter and more economical construction, yet will be more serviceable in use than conventional containers heretofore used.

Accordingly, it is a fundamental intention of this invention to provide a process and a means for reducing the pressures to which the confined liquids in such tanks are subjected; to utilize the thermodynamic forces developed within the body of liquids in such tanks for carrying out the method and actuating the apparatus designed to alleviate the above-mentioned detrimental conditions; and, in particular, to provide a refrigerating system in which the liquid itself constitutes the refrigerant, whereby the thermodynamic forces developed within the confined liquid will cause a circulation of the refrigerated portions of the liquid to thereby lower the temperatures existing in the liquid and hence reduce the thermodynamic pressures developed therein; and by further providing an extremely sensitive auxiliary refrigerating system incorporated in the above elements and which shall be periodically and intermittently operated by thermodynamic forces in confined bodies of liquids to effect the abovementioned functions and purposes.

This invention, therefore, has for its primary objects the development of improved methods and apparatus for reducing the peak or maximum pressures which are thermodynamically generated within confined bodies of volatile liquids.

A further object of the invention is to provide a method and apparatus wherein a portion of the volatile liquid is utilized to produce a refrigerating effect upon the main body of the liquid to thereby lessen the pressures to which the confined body of liquid is subjected.

Still another object of the invention is to provide method and apparatus wherein the thermodynamic pressures generated within a confined body of liquid are utilized to t mporarily discharge a portion of that liquid for reducing the ma pressure to which the confined body of liquid lS subjected.

Yet another very important object of the invention-resides in the provision of a method and apparatus as set forth in the preceding objects wherein the variations in pressure produced in a confined body of volatile liquid by the influence of varying temperatures thereon are utilized to effect a cyclic flow of a portion of the liquid out of and back into the confined body of liquid to thus reduce the extremes of pressure to which the confined liquid is subjected.

An additional object of the invention is to provide an apparatus and method in accordance with the preceding object wherein the cyclic circulation of liquid from the confined body is caused to suffer an expansion or drop in pressure during the course of its flow from and back into the confined body, which expansion is utilized to effect a refrigerating action upon the balance of the confined body of liquid.

Another very important object is to provide a very compact, efficient and improved conduit system for circulating a portion of the stored liquid for an efficient refrigerating action upon predetermined areas of the surface of the container, in heat exchange relation with and for cooling predetermined portions of the contents of the tank.

till another important object of the invention r sides in the provision of an apparatus and method as set forth in the foregoing objects wherein the liquid withdrawn from the storage compartment of the tank is removed from the cooler portions thereof, and wherein the circulating refrigerated portions of the liquid are re turned to the upper or warmer portions of the storage tank.

A further and very important object of the invention is to provide a method and apparatus for refrigerating confined bodies of liquids subjected to varying thermodynamic pressures therein by withdrawing, circulating and returning a portion of the confined liquids by means of the thermodynamic pressures to which they are subjected in the confined body, and by so arranging course of travel of the withdrawn portion as to subject that portion to the immediate influence of the external source of heat to which the confined body of liquid is subjected in order to thereby obtain a more rapid and hence more partment for confining bodies of volatile liquids and a vapor compartment, each of these compartments being sealed from the atmosphere, together with conduit means connecting these compartments for selectively effecting a flow of liquid from the liquid compartment to the vapor compartment and for effecting a return of liquid condensate from the vapor compartment into the confined liquid storage compartment.

A further feature of the invention resides in the provision of an apparatus as set forth in the preceding paragraph wherein pressure relief valve means are provided for controlling the flow of liquid through the conduit means from the storage compartment to the vapor compartment, for thereby effecting a reduction of pressure upon the withdrawn liquid for producing a vaporizing and refrigerating effect thereon.

An additional feature of the invention resides in the provision of a tank which is ideally adapted for use as a barge and wherein there are provided blisters upon the sides of the same for improving the stability of the barge, for increasing the constructional strength of the tank, and for assisting in cooling the contents of the same.

Yet another feature of the invention resides in the provision of a barge for the transportation of volatile liquids upon waterways, wherein the blister construction is arranged to overlie a portion of the vapor compartment formed within the barge to effect a greater cooling effect thereon sensitive fluctuation of pressure in the withdrawn portion of the liquid and in the confined body with a view to causing a more rapid series of intermittent refrigerating operations upon the confined body of liquid.

Another object of the invention is to provide a method and apparatus as set forth in the foregoing objects wherein provision is made for releasing the pressure upon the confined body of liquid and for venting the same, without loss of liquid or its vapor, to facilitate the loading or unloading of the tank.

An important feature of the invention resides in the provision of a storage tank or container which is divided by a partition into a storage comand to-thereby improve the refrigerating of the contents of the barge.

Another important feature of the invention resides in the provision of a barge having a lower confined liquid storage compartment and an upper confined vapor compartment, together with conduit means and mechanism for effecting periodic, cyclic circulations of liquid from the cooler portion of the confined body of liquid into the vapor chamber, reducing the pressure upon the liquid so inducted into the vapor chamber to produce a refrigerating effect therein, collecting the condensate of the liquid inducted into the vapor chamber in cooler portions thereof, subse quently returning the collected condensate the confined chamber at the hotter portions thereof.

Still another important feature of the invention resides in the provision of a container for volatiic liquids having separated liquid storage and vapor compartments, and wherein the vapor compart" ment is provided with sloping channels or gutters for collecting the liquid condensate therein into a sump together with conduit means for automatically and periodicallywithdrawing the condensate from the sump in response to pressure variations efiect'ed by the thermodynamic action of external sources'of heat upon confined portions of the volatile liquid.

These, together with various ancillary objects and features of the invention, which will later become apparent as the following description proceeds, are attached by this invention, preferred embodiments of the methods and apparatuses of which have been illustrated, byway of example only of the principles thereof, in the accompanying drawings, wherein:

Figure 1 is a side elevational view, parts being broken away, of the preferred embodiment of this invention, parts being shown in section, and illustrating the manner in which a storage tank is utilized as the main hull structure of a barge.

Figure 1A. is a fragmentary view taken in vertical transverse section substantially upon the plane indicated by the section line |l of Figure 2, through one embodiment of barge incorporating therein the principles of this invention and showing the arrangement of the refrigerating coils in connection with the storage and vapor chambers of this invention;

Figure 2 is a substantially horizontal sectional view taken substantially upon the plane indicated by the broken section line 2-2 of Figure 1A and illustrating in plan the arrangement of the recirculating, refrigerating and return conduit system forming a part of the embodiment of Figure 1;

Figure 3 is a view similar to Figure 1, taken substantially upon the plane indicated by the section line 3-3 of Figure 2, and illustrating the arrangement of the condensate collecting sump forming a part of the vapor chamber, and of the screened inlets of the return conduit system therein;

Figure 4 is a fragmentary sectional view taken upon an enlarged scale substantially upon the plane of the section line 4-4 of Figure 3 and illustrating the construction of a strainer and inlet valve forming a part of the return system of the invention;

Figure 5 is an enlarged detail view taken in vertical section and showing, in section, certain of the internal details of the arrangement shown in Figure 1 and, in particular, illustrating a combined condensate return valve and pressure release valve employed with this invention;

Figure 6 is a detail view taken in a vertical longitudinal section substantially upon the plane of the section line B6 of Figure 2 and illustrating the construction of the combined expansion and vent valve incorporated in the device;

Figure 7 is a sectional detail view taken substantially upon the plane of the section line l--T of Figure 6;

Figure 8 is an enlarged horizontal sectional view through a portion of the recirculating and refrigerating system of the invention; and

Figures 9-12 are diagrammatic views illustrating the cycle of operation of the recirculating and refrigerating system.

Reference is now made more specifically to the accompanyingdrawings, for an understanding of the principles of construction and features of operation of this invention, like numerals indicating similar parts throughout the various views, and the same numerals being employed as are used to designate corresponding parts in my copending application, Serial No. 39,154.

Disclosed in Figure 1 is a practical embodiment of a tank which has been modified to adapt the same to function as the hull or shell of a barge, in accordance with the basic concept of this invention. Although it is to be understood that the tank may be of various shapes and proportions and is not to be limited to that illustrated, a satisfactory embodiment may consist of a cylindrical elongated casing or container l0 having spherically rounded end portions l 2, this tank being of metallic plate or the like, although any suitable material may be employed having the requisite strength.

Within the tank In, and preferably, although not necessarily, extending throughout the entire length thereof, is a partition M which divides the tank into a lower compartment l6 constituting a storage chamber for receiving and containing volatile liquids therein, and an upper compartment 18 comprising a vapor chamber. As will readily be understood, the chambers l6 and I8 are completely sealed from each other by means of the partition l4, and preferably comprise pressure-tight chambers.

In this embodiment of the invention it will be seen that the partition [4 is shaped as an arcuate plate having its concave surface forming a part of the wall of a volatile liquid storage chamber 16, while its convex surface forms a part of the wall of the vapor chamber I8. The vapor chamber 1 8 is thus crescent shaped in cross section.

It will thus be seen that the convex surface of the partition [4 constitutes the bottom wall or floor of the vapor chamber I 8, and slopes from the center toward both sides thereof, and the junction of the partition 14 with the tank [9 thus provides a continuous trough or channel about the marginal edge of the partition [4.

In some instances, this trough or channel will be found sufficient for the purposes desired; but

it is preferred to accentuate such trough or channel by providing a depressed portion or portions 20 which constitute sumps for collecting and receiving vapor condensate therein as set forth hereinafter. If desired, these sumps 28 could extend around the entire periphery of the partition M, or alternately could be provided at predetermined spaced positions thereon. Moreover, the lower surfaces of those portions of the troughs or channels which define the sumps 29 will preferably slope upwardly from the sides of the sumps to the junction of the partition M with the tank l0, whereby ready collection and drainage of any vapor condensate within the compartment H3 will be effected and such condensate will be conducted to the lowermost portions of the sumps 20.

A conduit system to be specifically set forth hereinafter is provided for establishing controlled communication between the storage chamber t6 and the vapor chamber 18. It is contemplated that the storage chamber I6 shall be filled with the volatile liquid to be transported at all times, and said body of liquid completely filling the chamber I6 will be confined therein. The curved walls of the chamber l6 thus are ideally adapted to offer the maximum strength for retaining the confined liquid and the pressures generated therein by the thermodynamic action upon the confined liquid of varying increases in temperature effected by the suns rays upon the tank or by other external sources of heat. It is intended that when the tank is constructed as a barge, as illustrated in this embodiment of the invention, the continuously completely filled storage compartment IG and the vapor chamber is thereabove will be immersed into water to an extent indicated by the water line or level 22.

In order to promote the stability of the barge when the same is immersed in the water, a blister construction is secured thereto as by welding or in any other manner. struction consists of an arcuately shaped casing 2 which is secured to the tank I!) as by welding 26, or the like, and thus defines convex extensions protruding laterally from the walls of the tank [0.

I may prefer, in some instances, to extend this blister 24 as a continuous casing around the entire circumference of the tank [0, but in some instances I may prefer to form the blister as a series of spaced housings on one or both sides of the-tank ID, at either or both ends thereof.

This blister 0011- in accordance with the dictates of'the use whichis contemplated.

It is contemplated that the blisters or sponsons 24 will provide greater buoyancy for the barge, will improve the stability of the same against rocking or rolling as in heavy seas, will reinforce and strengthen the side walls of the barge, and will serve other purposes as set forth hereinafter.

The uppermost junction of the blister 2a with the wall it! will preferably be below the normal water line 22 of the loaded tank, but will overlie the line of junction of the partition l t with the wall 10, whereby the top of the blister will constitute a shield or screen which will tend to shade the sumps 29, and the vapor condensate collection troughs or channels from the direct heating effect of the suns rays or the like, and will further insulate the storage compartment from the heating effects of the relatively warmer, upper layer of water in which the tank is immersed, to thus assist in producing a cooling eifect upon these troughs, channels and the sumps 29. It should be here noted, and this principle is advantageously employed by this invention, that the temperature of open bodies of water even a slight distance below the surface remains at a relatively cooler and less rapidly variable temperature than the surface layer. Consequently, in a barge immersed therein, the lower portion of the barge and its contents will be substantially cooled relative to its upper portion.

Preferably secured, as by welding or the like, to the outer surfaces of the blisters 2 are rub rails 28, of any desired construction but preferably having vertical surfaces which act as buffers to shield and protect the blisters and hence the sides of the tank Hi from damages by collision, or the like, and which further may serve as abutment surfaces for securing a plurality of tanks together, in order to form a raft of tanks for more convenient pulling. Further secured to the blisters 2% in any desired locations thereon, as by welding or the like, are cleats (ill by means of which suitable cables may be attached to the barge for anchoring or moving the same. it should be here noted that the location of .the cleats upon the blisters is a desirable feature in that the strains transmitted to tank it by the cleats are thus distributed by means of the blisters 2% over a wider surface of the tank whereby the tank may be of much lig iter construction than if the cleats were d"- rectly attached thereto.

Surmounting the top surface of the tank it is a plurality of domes, any desired number being provided, two being indicated by the numerals 32 and 34, these domes conveniently but not necessarily consisting of tubular members secured to and passing through the upper surface of the tank l6 and extending thereabove to be provided with detachable closures or covare 35 of any desired construction. Preferably, one of these domes, such as that indicated at 32, provides a means for obtaining access to the vapor compartment l5, and to the mechanism housed therein; while another of the domes, such as that indicated at 3 5, extends through the vapor compartment i8 and is attached to the partition i l to provide a well or other chamber containing various control means for the mechanism with which the barge is provided.

Attention is now again directed to Figure 1 wherein it will be seen that the partition [4 is provided with suitable covers 52 which are hinged as at 5% for controlling manholes in the partition by means of which access may be obtained to the interior of the storage compartment it, these hinged manhole covers being provided with locking means such as a locking wheel 56 of any known and suitable construction. Obviously, any desired number of these manhole covers may be provided throughout the length of the partition M. It is to be understood that this construction may be employed in any of the various embodiments of the invention disclosed and set forth hereinafter, as desired.

Further, as shown in Figure 1, the sumps 20 may be provided with detachable covers or closure plates 53 likewise of any suitable design, by means of which access may be had to the sumps 29 for inspection or cleaning the same, from the interior of the compartment [6.

A pressure relief or safety device means is provided for preventing the attainment of a pressure in the vapor chamber it above a pre determined desired safe maximum pressure, and

r for this purpose, as shown in Figure 1, there is provided a conduit 59, extending through the tower 35 into the interior of the vapor compartment l8, which conduit has an outer end Gil extending through the upper wall of the tower 34 into free communication with the atmosphere, a suitable pressure relief valve 62 of any desired construction being included in the conduit and preferably positioned within the well defined by the tower 3 3 for easy access thereto for inspection, repairs or adjustment of the valve as desired. By this means, provision is made for preventing the pressure within the vapor chamber l8 from exceeding a predetermined value for which the valve 82 is set.

It will be evident that when the volatile liquid storage compartment 66 is completely filled with liquid in accordance with conventional practice during the transportation or storage of liquids in tanks such as those with which the present invention is concerned, that when the temperature to which the confined liquid subjected is increased, there is a corresponding pressure increase upon the confined liquid, since there is no space for expansion within the storage compartment l6, and since the metallic walls of the same are of negligible expansive qualities. Obviously, if some means were not provided for decreasing the pressures thermodynamically generated within the confined liquid, dangerous pressures would soon be reached which would threaten the rupture of the tank which would be attended by various hazards. In accordance with the basic concept of this invention, means are provided for, first, withdrawing some of the contents of the storage compartment It for directly lowering the pressure thereof, second, utilizing the pressure drop of the withdrawn portion of the contents to produce a refrigerating eifect which will tend to lower the temperature and thus further reduce the pressure of the confined liquid within the compartment it, and, third, when the contents of the storage compartment H5 have relatively cooled so that the remaining liquid therein would be subjected to a sub-atmospheric pressure or a relatively reduced pressure below normal upon cooling of the tank, to reintroduce the withdrawn portion of the liquid to restore or equalize the pressure within the compartment It to its original value.

volatile storage chamber As shown in the enlarged detail view of Figure 4, the inlet means 90 preferably consists of a housing or casing which may be generally pear-shaped, and is provided with apertures 98. therein, being covered as by a screen I00, this casing being disposed near the bottom of the pockets or sumps 20. This casing is threaded upon one end of a nipple I02 whose upper end is secured to a valve casing I04 which, in turn, depends from the screw-threadedend of the return pipe 92. The valve casing is preferably provided with a suitable check valve I06 which is illustrated as being of the well-known ball construction and closed by means of a spring I against a seat formed in the lower end of the casing I04, to thereby permit flow into the pipe I'IZ from the casing 90, but to prevent return flow. As will be readily understood, various forms of check valves may be employed for this purpose, such as flap valves, or the like. However, the influence of gravity may be relied upon to close the valve, but it ispreferred to substitute or assist in this closing action by means of a spring such as that shown.

The valve casing I04 may be provided with a removable plug IIO to obtain access to the same for inspecting, repairing or servicing the check valve as necessity requires.

The present arrangement presents a refrigerating system which is very sensitive to tem perature changes and to relatively small temperature differences between the vapor and storage chambers. In this arrangement, the tank I0, divided by the partition I4 into the I6 and the vapor chamber I0, is provided with concentric fluid discharge and return conduits. In the embodiment chosen to illustrate the principles of this type of construction, the discharge or refrigerating conduit system has been shown as the exterior conduit, while the return conduit system has been shown as the interior conduit of the concentric arrangement. However, it will be understood that the principles permit of the reversing of this arrangement, wherever the same is found to be expedient or preferable. As will be seen by reference to Figures 3 and 5, the central top portion of the upwardly curving partition I4 is provided at its highest location with one or more pipes I 6| freely communicating with the interior of the storage compartment I0 to provide an outer, return line therefor, while disposed centrally of the return pipe I6I is an outlet pipe I63 whose lower end may conveniently extend into the cooler portions of the compartment I6 and, if desired, into close juxtaposition to the bottom wall thereof as shown in Figure 3. At this upper end, the discharge conduit I03 communicates with a fitting I62 from which extend nipples I64 forming part of a piping connection with expansion valve assemblies the upwardly extending terminal portions of the refrigerating coils I08 which extend through the partition I4 into the tower 34 where the abovernentioned pressure reduction valves and fittings are located. This refrigerating and expansion coil I68 is then disposed with return bends upon the under surface of the partition I4 in intimate heat exchange relation therewith as will be clearly apparent from Figures 1-3, and may be above or on both sides of the partition as in Figure 1A.

As shown best in Figure 5, the outermost and return conduit I6I has lateral extensions I10 I66 which, in turn, are connected with a is urged to its seat, as by a spring Ill The other end of the refrigerating conduit I68 extends through the partition I4 as shown in Figure 3 and discharges to the outer surface thereof into the vapor compartment I8, while the corresponding end of the inner conduit I12, constituting a return conduit, is connected as shown in Figure 3 with the check valve housings I04 and liquid inlet members disposed in the sumps 20, which construction may be substantially identical with that previously described with regard to these elements. It should thus be particularly noted that there are two check valves, the assembly I04 and the assembly I14, for the two terminals of the return lines, for a purpose to be later set forth. The

discharge and expansion conduit system I68 may be provided with suitable spray nozzles or the like for diffusing the fluid emitted thereby into various portions of the vapor chamber I8.

Preferably, the pressure release valves I66 are spring loaded to maintain a desired pressure within the storage compartment I 6 so that when this pressure is exceeded by the above-mentioned thermodynamic action of temperature upon the volatile liquids within the storage compartment, the rising pressure will force a portion of the liquids through the outlet conduit system, through the spray nozzles, and discharge the same into the vapor compartment I8.

It is very important to here observe that as this flow of a portion of the volatile liquid is effected from the storage compartment I6 under the influence of the rising pressures therein which exceed the pressure for which the release valves I 66 have been set, the discharging liquid in passing the spring-loaded pressure relief valves will be subjected to a pressure drop or will be expanded in its travel through the following conduit system. As is well known, fluids, when subjected to a diminution of pressure and expanded, are refrigerated or chilled thereby, and the present invention makes use of this pressure drop of the discharge or withdrawn fluids to efiect a refrigerating or cooling action upon the tank.

As will be furtherunderstood, the magnitude of the cooling action can be somewhat proportioned or regulated by properly adjusting the differences in pressure maintained in the storage compartment I6 by the loading of the pressure release valve I62 or I66 and the pressure maintained as a maximum in the vapor compartment I8 "by means of the safety release valve 62.

As will be evident, the ejection of a portion of the contents of the tank I6 will thus serve to reduce the pressure rises created in the storage compartment as the liquid contents thereof are expanded by heat, and the pressure rise therein is further alleviated by the refrigerating or cooling action which converts the pressure drop of the expelled liquids in the vapor chamber into a heat absorbing medium for thereby cooling the partition I4 and hence the upper portion of the contents of the storage tank I6 which immediately underlies the partition. As will be seen, it is the upper portion of the tank which is subjected to the greatest effects of the temperature rise of the confined liquids, and hence the refri erating action is thereby most efiiciently applied.

As shown more clearly in Figure 2, the upper end of the return conduit 55! is provided with a head or housing portion E89 having the above mentioned lateral extensions lid, this portion 586 being provided with a manually operable pressure release or venting valve, indicated generally by the numeral 582, which is operable to vent the interior of the storage compartment iii to the vapor chamber is when it is desired to fill or empty the storage compartment, and thus avoid filling or emptying the same against a varying pressure therein. This valve construction includes a tubular conduit lfiii having its lower end communicating with the interior of the head portion E80, and having a discharge opening 68:? which is in communication with the interior of the vapor compartment IS. The inlet end of the conduit IE4 is controlled by a downwardly open ing valve I53 which may be of the poppet type, if desired, and which is provided with a valve control stem 192 rigidly attached thereto, said stem having a plunger it-i guidingly and slidingly received in the tubular conduit {85, a valve closing spring E96 being engaged between the lower end of the plunger led and a suitable spring seat whereby the valve is urged by the spring to its closed position.

The upper end of the valve stem I92 is pivotally connected, as at I98, to an operating lever 2st, suitably journaled upon a support, the outer end of this operating lever being pivoted, as at 2&2, to the end or an operating handle or lever 2%.

The arrangement is such that when the lever 2% is rotated in a counter-clockwise direction, as viewed in Figure 5, the lever 2M1 is oscillated in a clockwise direction to thereby force the valve 58%?- from its seat and thereby vent the interior of the compartment It to the interior of the vapor compartment Hi. It will be noted that the extremity of the lever 204 is provided with a cam or eccentric member 296 which is adapted to abut against a surface carried by a bracket 258, whereby the valve may be locked in its open position by throwing the lever 2534 in a counter-clockwise direction.

Referring again to Figure 2 particularly, it will be seen that the upper end of the discharge conduit l3 is connected as by a laterally extending pipe 2 i i to the above-mentioned valve fitting 162, whose construction is shown best in Figures 6 and 7.

The valve fitting IE2 is provided with a tapered valve seat 2!? upon which is removably seated a valve member 2 it having a valve stem ZIS. This valve is guided for sliding movement in the valve chamber by means of longitudinally extending guide ribs 2E8, see Figure '7, which define a plurality of parallel liquid flow channels 220 therebetween, by means of which fluid may be discharged from the conduit 2 l past the valve and guide ribs 215 into the valve fitting Hi2 and from thence by means of the pressure reduction valves l & into the refrigerating conduit system HES. The valve 2 M is resiliently urged against the seat by means or" a coil spring 222 which surrounds the valve stem 2l6 and abuts against the guide ribs 2% at one extremity and a retaining collar 22:! suitably received in a recess 225 in a sleeve 223 which is screw-threadedly engaged in a bore 238 in the outer end or" the valve casing 562. This sleeve is provided with an operating handle 232 by means of which the sleeve 223 may be moved inwardly and outwardly of the fitting I62,

The operation of this embodiment of the circulating and refrigerating system will now be described. With particular reference to t; e diagrammatic views of Figures 9-l2, the operation is as follows: When the compartment it is filled initially with volatile liquid, a certain quantity of liquid is permitted to overflow the filling port, to thereby provide an accumulation of liquid in the sump 26, such as to the level indicated the dotted line 23 This liquid serves to prime and submerge the inlet members it of the return line H2, and insures that there will be sufilcient liquid present in the combined vapor and storage co1npartments of the tank it to at all times fill the conduit systems during operation while maintaining the compartment IS entirely filled with liquid. It is desired to here emphasize that throughout the entire operation of this apparatus and method the pressure within the storage oompartment IE will preferably be above atmospheric pressure.

The diagrammatic view of Figure 9 discloses the conditions prevailing in the apparatus when the pressure within the storage chamber it has risen relative to the pressure of the vapor chamber it, because of the inflow of heat into the tanir. This rise in temperature, elfecting a rise in pressure in the storage compartment is, has, as shown in Figure 9, started a flow of liquid from the cooler portions of the tank upwardly through the discharge conduit i63 in the direction indicated by the arrows,'has unseated the expansion valves E85 against the opposition of their closing springs, and has started a how of the pressurized discharge liquid through the refrigerating and pressure reducing discharge conduits as shown by the arrows therein, this flow into the sealed vapor compartment i8 tending to raise the pressure therein. This rise in pressure in the vapor compartment, applied to the level 23 2 of the liquid already contained therein, increases the pressure to which such liquid is subjected and causes a flow into the inlet member ss, as indicated by the arrows, and some of this liquid will pass the spring-opened check valve N36 to enter the return conduit H2 and fill the same as in icated by the arrows therein. However, the check valves H6 adjacent the discharge end of the return conduit, and which are normally closed by their closure springs lit, are further positively closed, since they are subjected to the increased pres sure within the storage chamber it by means of the free communication of the latter through the return conduit or pipe it I.

It will thus be seen that during the initial stage of the operation, the rise in pressure in the storage tank has produced an outward flow of the cooler portion of the liquid therein, and has, at the same time, positively closed the check return valves I at the upper or discharge ends of the return conduits, and has further forced liquid into the return conduits or increased the pressure therein. After passing the pressure reduction valves Hit, the fluid in the conduits Hi3 is chilled thereby and absorbs heat from the return conduit H2, thereby refrigerating the latter as well as the walls of the conduit E68 and all parts with which the latter is in heat exchange relation. This chilling of the conduit I12 and its contents lowers the pressure therein, thereby assisting the augmented pressure imposed on the liquid level 234 in filling conduit I12. This action tends to prolong the flow and circulatory movement of fluids. This action has further resulted in lowering the pressure within the storage compartment therein is subjected.

When now a new ratio of pressures has been established between the storage and vapor compartments, by reason of the reduction of pressure in the storage tank from its maximum increased pressure, and by the above mentioned cooling effects, the condition depicted in Figure will prevail. Since the pressures between the tanks I6 and I8 have reached equilibrium, there will be a temporary cessation of flow through the discharge conduit I63, as shown by the doubleheaded arrow therein, and consequently the reducing valves I66 will be closed against their seats by their springs and there will be no flow through the refrigerating conduit I 68, as indicated by the absence of flow arrows therein. However, the reduction of the pressure within the storage compartment I6 by reason of the cooling and partial withdrawal of the liquid therein now leaves the vapor compartment and the conduit I12 at a relatively higher pressure which would be augmented by the inflow of heat with the vapor compartment, which pressure forces open the springclosed valves I66 and induces a flow of liquid from the sump 20, as indicated by the arrows, through the return conduit I 12, and this pressure difference forces open the check valves I16 and forces liquid from the sump 26 through the return conduit I6I and back into the interior of the storage compartment I6, as indicated by the arrows in Figure 10, this action continuing until the pressures of the chambers I6 and I8 are again in equilibrium.

It should be here noted that during the latter part of this return flow, the pressure in chamber I8 may drop below that in the conduit I12 whereupon the valves I66 will close. As the elevated pressure and heat in conduit I12 acts against the closed valves I66 and the liquid trapped thereby,

a flow is induced past valve I16 into chamber it.

This causes a pressure rise which, in turn, may (depending upon the pressures involved and the closing bias of valve I66) cause a flow from I6 through the discharge conduit I63 and passages I58 into vapor compartment I8.

The above described operation represents the refrigerating circulating primary cycle of the de vice, and as hereinbefore mentioned, this cycle of operation is effected at relatively long intervals of time by the creation of a sufficient pressure differential between the relatively large volumes contained in the storage and vapor chambers.

However, a portion of this apparatus is capable of much more frequent and sensitive operation, and its, functioning constitutes what may be termed the sensitive or secondary refrigerating and circulating system. When the above described pressure equilibrium has been reached after the operation described in connection with Figure 10 has been effected, the condition shown in Figure 11 will exist wherein there is no flow of fluid between the chambers. However, since it is assumed that the tank is constantly sub jected to an inflow of heat from an external source, such as the suns rays or the like, it will be appreciated that the vapor compartment, and hence the conduit system associated therewith, and which overlies the storage compartment, will be heated faster than the bulk of the liquid in the storage compartment. Consequently, the relatively small quantity of fluid which is trapped and retained in the return conduit I112 between the inlet and discharge check valves I66 and :16 thereof will be subjected to a relatively rapid rise in temperature and a resultant relatively rapid increase in pressure over the change of temperature and pressure of the body of liquid in the storage chamber. This rise in pressure within the return conduit thus closes the check valve 56% and forces open the check valve I16, thereby inducing a flow of fluid through the return conduit iiii into the tank storage compartment It as indicated by the arrows in Figure 11.

It will be noted that this return flow just men tioned may be assisted by and, in fact, may even be occasioned by the increased pressure generated in the vapor compartment I8 by the relatively rapid heating thereof.

When the initial stage of the operation indicated in Figure 11 has been completed, it will be seen that the liquid return to the storage chamber I6 will produce a pressure rise therein, whereby the pressure within the chamber I6 will then be somewhat above that prevailing in the chamber [8. Accordingly, as indicated in Figure 12, the increased pressure in the chamber I6 will induce a flow as shown by the arrows, through the discharge conduit I63, and thence through the pressure reduction valve I66, into and thro h the refrigerating conduit I68.

It will be readily apparent that there is produced a step-by-step movement of liquid from the cooler portions of the storage chamber, through the discharge conduit and refrigerating coils connected thereto, to the relatively more highly heated vapor chamber; thus producing a cooling effect therein as well as on the upper portion of the storage chamber, this being followed by a return of the cooled or chilled discharged fluid through the return conduits into the hotter portions of the storage chamber, thus effecting a mixing action of the hotter and cooler portions of the liquid within the storage chamber as well as utilizing the thermodynamic forces of the external source of heat to cause this operation and minimize the temperature and pressure extremes heretofore encountered in storing volatile liquids and fluids in sealed containers.

It is to be particularly noted that it is an inherent function of this heat exchange arrangement of the discharge and return conduits to effect a prolongation of the discharge flow through the discharge conduit I63, since when the systems are full of fluid and in the condition indicated in Figure 9, the outward flow through the discharge conduit I63 into'the lower pressure of the vapor chamber will be accompanied by a gradual reduction of the pressure within the chamber I6, until just prior to the condition indicated in Figure 10, when there will be a simultaneous outflow through the conduit I63 accompanied by a smaller inflow through the conduit I6I, this inflow being occasioned by the reduc" tion of pressure against the check valve I16, while the check valve l 66 remains closed.

Obviously, in the sensitizing or secondary circulatory system, the conduits I 12 with their inlet and outlet check valves I 66 and I16 actually function as fluid pumps for repeatedly and intermittently delivering liquid from the sumps 20 into the tank I6, such inlet of liquid occasioning a corresponding outflow from the discharge conduit I53. It will be evident that the motivating and controlling factor for this cyclic operation is a '15 constantly varying relative pressures existing in the compartment It, the compartment i8, and the chambers which are defined by the return conduits H2.

It will be seen that during operation of the system, cooling action occurs in at least five distinct phases or actions, as follows:

(1) By means of a direct flow of heat between the heat conducting walls between the two fluids at different temperatures, as by the fiow of heat betwe n chambers 16 and I8 through the partition It and/ or the walls of the tank it}, a similar flow between the refrigerating coils and the return conduits, as well as between either chamher and/ or the conduit system and the surrounding water medium.

(2) By means of the pressure reduction in the confined body when fluid is withdrawn or expelled therefrom, this cooling action being effected during and supplementing that of the preceding para graph.

(3) By means of the expansion of the withdrawn fluid into a lower pressure zone whereby it is chilled and absorbs heat from its surroundings, as during the fluid flow through the pipe system I58 and H2.

(4) By means of the expulsion of vapor accompanied possibly by some fluid not entirely vaporized from the end of the concentric tube I68 into the vapor chamber l8, this vaporization produc ing a further heat absorption and cooling action.

(5) By means of the pressure reduction in the vapor chamber l8 when there is a withdrawal of fluid therefrom by the tubing H2.

I desire it to be distinctly understood that although the secondary system has been described and may very efficiently consist of concentric discharge and return conduits, yet various other relative arrangements of these conduits disposed at different positions in the storage and vapor chambers could be employed as necessity dictates. Moreover, if desired, thes conduits could be provided and arranged in substantially non-heat exchange relation with respect to each other, the effect of this being that the discharge and return flows of the cycle of operation would be of greater duration and would occur at less frequent intervals than when the pipes are disposed in the above-mentioned intimate heat exchange relation with respect to each other.

t is to be further understood that although the illustrations have depicted the partition M as either concaved or convexed with respect to the walls of the tank it, the invention may be realized by partitions of various other configurations. For example, a partition having planar, sloping sides may be employed and the discharged liquid be caused to flow down the sloping sides to a collection trough or troughs, both to provide the cooling action desired as well as to collect and accumulate the discharged liquids in sumps. The rate of flow over the sloping surfaces, whether planar or curved, may be utilized more efficiently by providing baffles or channels thereon to cause the descending liquid to follow more or less tortuous paths and hence prolong its heat exchange relation with the surface of the partition.

It will, of course, be evident that the various valves will be calibrated or adjusted to allow for the various hydrostatic heads to which they may be exposed.

It should be especially noted that the method and apparatus set forth hereinbefore all possess the advantage that they are capable of use in storage systems wherein th vapors generated by and accompanying the storage of volatile liquids are in themselves possessed of suiiicient value to warrant provision for their retention and salvag ing. The practicing of this invention in such environments thus does not necessitate the creation or" additional storage compartments for either liquid or vapor, but merely advantageously utilizes such existing features of construction.

From the foregoing, it is thought that the mode of employing the method and apparatus hereinbefore set forth, together with their nu merous advantages, will be readily apparent, and further explanation is believed to he unnecessary. However, since numerous modifications and changes falling within the purview of the invention will be readily understood by those skilled in the art after a consideration of the foregoing specification'and accompanying drawings, it is not desired to limit the invention to the exact method and constructions shown or described in the foregoing specification and annexed drawings, except as required by the appended claims.

Having described the invention, what is claimed as new is:

1. The method of maintaining a con-fined b of fluid which is subjected to extern effects below a predetermined tempo. 1 pressure, which comprises, educting a porn of the fluid when said confined body said predetermined pressure, cooling said on I portion, placing said cooled portion in To change relation to said confined body, di ing said cooled portion into a confined inducing a unidirectional, intermittent flo. f a part of said discharged portion into a 1e zone and returning said part of discl' portion from said restricted zone in a uni-d ceeds that of the confined body, the flow from the confined body and the return iiow from the restricted zone to the confined being conducted in paths in heat exchan. lation to each other.

2. The method of claim 1 wherein said paths are in concentric relation to each other.

3. An apparatus for storing fiuids comprising sealed storage and vapor compartments, discharge means responsive to a predetermined pressure for discharging fluid from said storage to said vapor compartment, means for cooling the discharged fluid, conduits for placing the cooled fluid in heat exchange relation with storage compartment and return means for returning fluid from said vapor to said storage compartment when the pressure in the former exceeds that of the latter, said discharge and return means being in heat exchange relation.

4. The combination of claim 3 wherein discharge and return means are concentrically disposed.

5. A method for reducing the pressure thermcdynamically generated by external heat in in response to pressures above a prede mined limit, reducing the pressure and thereby the temperature of the withdrawn portion while the latter traverses the discharge conduit, placing the discharge conduit in thermally conductive relation to the contents of said storage sources in confined bodies of volatile liquids having liquid and vapor storage chambers and discharge and return conduits each communicating with both of said chambers, comprising cooling the contents of the storage chamber by withdrawing a portion of the fluid confined therein in response to pressures above a predetermined limit, reducing the pressure and thereby the temperature of the withdrawn portion while the latter traverses the discharge conduit, placing the discharge conduit in thermally conductive relation to the contents of said storage chamber for additionally cooling the latter, prolonging the period of pressure reduction and hence of heat exchange between said conduits by placing the return conduit in thermally conductive relation to said discharge conduit for causing heat flow therebetween and causing a flow of said with-' drawn portion through said return conduit into said storage chamber when the pressure in the return conduit exceeds that in the storage chamber by a predetermined value.

7 The method of claim wherein the last mentioned step is effected at chronologically spaced intervals.

8. That method for reducing the pressures thermodynamically generated by external heating in confined bodies of volatile liquids having storage and vapor chambers connected by di charge and return conduits, which includes s quentially transferring liquid between the sto age and vapor chambers in response to predetermined pressure difierences therebetween while maintaining the storage chamber continuously filled with liquid, lowering the pressure of the withdrawn liquid during transit to decrease its temperature and cooling the confined body by direct heat exchange with the fluid in the vapor compartment and with an external coolant, by lowering the pressure within the confined body and by the absorption of heat therefrom by the pressure reduction in the withdrawn liquid, the duration of the, flow through the discharge conduit being prolonged by the reduction in pressure in the return conduit occasioned by the absorption of heat from the fluid in the return conduit by the fluid in the discharge conduit.

9. That method for reducing the pressures thermodynamically generated by external heating in confined bodies of volatile liquids having storage and vapor chambers connected by discharge and return conduits, which includes sequentially transferring liquid between the storage and vapor chambers in response to predetermined pressure difference therebetween while maintaining the storage chamber continuously filled with liquid, lowering the pressure of the withdrawn liquid during transit to decrease its temperature and cooling the confined body by direct heat exchange with the fluid in the vapor compartment and with an external coolant, by lowering the pressure within the confined body and by the absorption of heat therefrom by the pressure reduction in the withdrawn liquid, the further step of conducting the withdrawn fluid in concentric paths 1 8 in heat exchange relation through the discharge and return conduits.

10. An apparatus for storing volatile liquids comprising storage and vapor compartments separated from each other by a partition and sealed from the atmosphere, discharge means responsive to a predetermined pressure ratio in said compartments for discharging fluid from the storage to the vapor compartment and return means responsive to another predetermined pressure ratio in said compartments for returning fluid from the vapor to the storage compartment, one of said means including a conduit disposed in direct contact and heat exchange relation to said partition and having portions disposed in both said compartments and in heat exchange relation therewith.

11. An apparatus for storing volatile liquids comprising storage and vapor compartments separated from each other by a partition and sealed from the atmosphere, discharge means responsive to a predetermined pressure ratio in said compartments for discharging fluid from the storage to the vapor compartment and return means responsive to another predetermined pressure ratio in said compartments for returning fluid from the vapor to the storage compartment, each of said means including a conduit disposed in direct contact and heat exchange relation to said partition and having portions disposed in both said compartments and in heat exchange relation therewith.

12. The combination of claim 10 wherein the other of said means includes a second conduit in heat exchange relation to said first mentioned conduit.

13. The combination of claim 12, wherein said conduits are concentrically disposed.

14. An apparatus for storing volatile liquids comprising storage and vapor compartments separated from each other by a partition and sealed from the atmosphere, discharge means responsive to a predetermined pressure ratio in said compartments for discharging fluid from the storage to the vapor compartment and return means responsive to another predetermined pressure ratio in said compartments for returning fluid from the vapor to the storage compartment, said discharge and return means each including a conduit, said conduits being disposed in heat exchange relation, one of said conduits having therein thermally actuated means for pumping fluid unidirectionally with an intermittent flow.

15. The combination of claim 14, wherein said last means comprises a pair of said non-return valves both opening in the direction of flow.

16. The combination of claim 10, including means to directly vent the compartments to each other.

17. An apparatus for storing volatile liquids comprising storage and vapor compartments sealed from the atmosphere, discharge means responsive to a predetermined pressure ratio in said compartments for discharging fluid from the storage,to the vapor compartment and return means responsive to another predetermined pressure ratio in said compartments for returning fluid from the vapor to the storage compartment, one of said means including a conduit disposed in direct contact and heat exchange relation to both of said compartments and having portions disposed in each of said compartments.

18. The combination of claim 1? wherein the other of said means includes a second conduit in 19 heat exchange relation to said first-mentioned conduit.

19. The combination of claim 17 wherein the other of said means includes a second conduit in heat exchange relation to said first-mentioned conduit, said conduits being eccentrically disposed.

20. An apparatus for storing volatile liquids comprising storage and vapor compartments sealed from the atmosphere, discharge means responsive to a predetermined pressure ratio in said compartments for discharging fluid from the storage to the vapor compartment and return means responsive to another predetermined pressure ratio in said compartments for returning fluid from the vapor to the storage compartment, said discharge and return means each including a conduit, said conduits being disposed in heat exchange relation, one of said conduits having thermally actuated means for pumping fluid unidirectionally with an intermittent flow.

21. The combination of claim 1'7 including means associated with one of said conduits to directly vent the compartments to each other.

References Cited in the file of this patent UNITED STATES PATENTS 

